1. Field of the Invention
This invention relates generally to metal detectors and more particularly to an apparatus for quickly finding wall studs and other items containing ferrous components but which are located behind wall surfaces and the like.
2. Description of the Related Art
The prior art teaches that magnets may be used to detect hidden objects containing iron or nickel metal components. Such magnets have been used to find nails and studs in and behind walls. However, the prior art does not teach that such a magnet may be constructed as defined herein and used as so defined in order to improve the ability of a workman to very quickly establish the location of a metal stud with precision. The present invention fulfills these needs and provides further related advantages as described in the following summary. Stud finders are common and use a variety of principles. A very common device having a trademark: StudSensor(trademark) is manufactured and distributed by Zircon Manufacturing, Inc. and protected by U.S. Pat. No. 4,099,118. Such devices use a capacitive or inductive reactance technique for sensing the presence of hidden objects. These devices are relatively expensive, slow in use and easily damaged. They also require batteries which require replacement from time to time.
The present invention teaches certain benefits in construction and use which give rise to the objectives described below.
The present invention uses an elongated magnet having a round and smooth outer surface. The magnet is attached at one of its ends to a bead chain wherein each of he beads is able to rotate relative to the next so that the magnet is essentially free of any restriction in rotating with respect to the chain. In use the magnet is held dangling from the bead chain and moved across a wall until it detects a metal object within the wall. The magnet then rotates until it places itself at the center of the object. The invention distinguishes between metal and wood studs by the aggressiveness by which the magnet moves toward the metal object, i.e., quickly for studs and more slowly toward nails and screws. It is immune to false action due to nearby electrical or plumbing lines since neither interfere with the magnetic attraction between the invention and iron bearing objects. The invention does not require reading of scales, observance and interpretation of blinking lights and does not mark the walls in which it comes into contact.
A primary objective of the present invention is to provide a metal detector for finding hidden objects having advantages not taught by the prior art.
Another objective is to provide such an invention capable of finding wall studs and other metal objects within a wall.
A further objective is to provide such an invention capable of quickly establishing the vertical center line of a wall stud.
A still further objective is to provide such an invention capable of being fabricated and brought to market at a very low relative price.